Recent years have seen advancement of cloud computing technology. Infrastructure as a Service (IaaS) has been widely used to lease virtual machines running on a physical host to users.
In IaaS, a user is called a tenant. One tenant typically uses a plurality of virtual machines. In view of disaster planning and business continuity, there is a trend to deploy IaaS infrastructures to a plurality of physically remote locations and connect the IaaS infrastructures to operate them as a single virtual IaaS infrastructure.
Regarding IaaS, live-migration techniques are being developed that transfer running virtual machines to another physical host. Live-migration techniques are implemented in a kernel-based virtual machine (KVM) of Linux (registered trademark), VMotion of VMware, Inc., and the like. For example, a virtual machine running on a physical host is transferred to another physical host depending on operation statuses of the physical hosts on a platform that IaaS is built on.
PTL1 describes a technology regarding a virtual-environment management system. The technology described in PTL1 includes a detection means for detecting a job for starting communication processing between virtual machines, a determination means for determining whether the cost of the communication processing, which is conducted by the job detected by the detection means, is equal to or greater than a certain amount, and an arrangement means for arranging the virtual machines so as to cause the virtual machines starting the communication processing to run on the same host machine when the determination means determines that the cost of the communication processing is equal to or greater than the certain amount.